Chapter 1 of 7

Geometric Twins

When are two shapes exact copies? Find out which measurements are enough to make two triangles match, and use that to prove new facts.

1. 1The Signboard Problem
2. 2What You Already Know
3. 3What Do You Already Think?
4. 4Why Three Angles Are Not Enough
5. 5Same Arms, Different Symbols
6. 6Swing the Arm, Change the Symbol